The present invention relates generally to pallets for storing and moving items and, in particular, to a support rail for a pallet that is formed from a folded sheet of corrugated paperboard.
Pallets and other platforms for storing and carrying loads are well known in the art. Traditionally, pallets have been made of wood and sometimes metal. More recently, pallets have been made of corrugated paperboard. Such pallets have several advantages, for example, they typically cost and weight less than wood, and they can be readily recycled at the end of their useful lives. However, corrugated paperboard pallets have their drawbacks, for example, they are generally not sufficiently strong or durable to be used in many of the applications where wood pallets are used.
There are several known corrugated paperboard pallets that attempt to overcome these deficiencies. For example, U.S. Pat. No. 4,563,377 to Melli discloses a pallet made of tubular beams each formed by a sheet having number of cardboard panels folded over on themselves. Because of the relatively large number of panels per sheet, these beams provide for a substantially increased strength relative to hollow cardboard beams.
However, this beam configuration has a number of disadvantages, including that each beam has two exposed corrugated sheet ends at the top center portion of the beam. The sheet ends expose the open corrugated flutes of the interior of the paperboard to moisture and other debris, the intrusion of which tends to weaken and reduce the useful life of the beam. Also, the beam has eight inward folds and six outward folds. With so many folds against each other, this beam would be extremely hard to fold, so the use of some heavier gauge cardboard sheets may not be practical. In order to still accomplish the needed strength, the relatively large number of panels (fifteen) is provided, which results in a large number of folding steps (fourteen) and gluing steps (seven glue areas total per beam).
A similar pallet beam is disclosed by U.S. Pat. No. 5,423,270 to Kilpatrick et al. This beam or stringer suffers from similar deficiencies due to the relatively large number of panels (thirteen), folding steps (twelve), and glue steps (five) per beam, without appreciably increasing the strength of the resulting beam.
Additional corrugated paperboard pallets and beams are disclosed by U.S. Pat. No. 5,285,731 to McIntyre and U.S. Pat. No. 5,377,600 to Speese et al. The beams of each of these patents have openings extending laterally through them for receiving the arms of a forklift. These beam arrangements make the pallets much easier to use in most warehouse applications where a forklift is used. However, the lateral openings through the beams significantly reduce the strength of the beams. Therefore, additional reinforcing members, complex cutting and folding of support flaps, and/or thicker top pallet members are required, thereby increasing the material and manufacturing costs of the pallets.
Accordingly, it can be seen that none of these pallets has proven entirely satisfactory. Therefore, a need yet remains for a corrugated paperboard pallet rail that is strong and durable, but lightweight and inexpensive to manufacture. It is to the provision of such an article that the present invention is primarily directed.
Briefly described, the present invention comprises a sheet of corrugated paperboard that is formed into eleven panels, including a central panel, two end panels, and eight intermediate panels, all interconnected together at fold lines so that the sheet can be folded to form a rail for withstanding a load. The sheet can be folded to form a rail with only six vertical support panels and two diagonal support panels, only two folds against the prevailing fold direction, and only three glue areas, so that a heavy gauge material can be used to provide the strength needed for paperboard pallets. The rail formed thereby is useful to withstand loads applied by items placed on a pallet that includes the rails, by lateral impacts to cartons including such rails, by vertical loads on cartons including the rails, or otherwise.
In a first exemplary embodiment, the rail has two transverse channels and two support portions each formed by a set of openings in the sheet that are aligned when the sheet is folded to form the rail. The openings include a central opening in the central panel and the two adjacent intermediate panels, two intermediate openings in two other of the intermediate panels, and two end openings in the end panels. In this manner, the channels can be sized and shaped to receive an arm of a forklift rendering the rail well-suited for use in a pallet.
In a second exemplary embodiment, the rail has three transverse channels with a semi-circular shape. In this manner, the rail can be used in packaging and/or storage applications to support three items with a similar shape to prevent damaging them from accidental dropping or rolling. Alternatively, another number and shape of channels can be provided. In a third exemplary embodiment, the rail does not have any channels, and is best suited for applications requiring the highest strength.
In fourth and fifth exemplary embodiments, the rail has an additional fold line enabling the panels to be folded into two rail sections angled from each other, for use as corner rails in cartons or other packaging. In the fourth embodiment, the rail has corrugated ribs in the longitudinal direction for higher compression strength, for use as a post to protect the contents of the carton when stacked. In the fifth embodiment, the rail has corrugated ribs in the transverse direction for absorbing side impacts and creating a buffer space within the carton. In the sixth embodiment, the rail does not include the end panels, thereby providing the appropriate strength for low-load applications while reducing the material and assembly costs of the rail.